Dry pipe/deluge valve for automatic sprinkler systems

ABSTRACT

A dry pipe valve is provided which includes a main chamber having an input port for receiving fluid from a supply line and further having an output port. The dry pipe valve further includes a clapper assembly installed in the main chamber for sealing the input port. The clapper assembly includes a clapper configured to seal the input port, where the clapper is hinged to the main chamber. The clapper assembly further includes a hinged lever movable between a first position in which the clapper is held closed by the lever and a second position in which the clapper is allowed to open. The dry pipe valve also includes a pushrod mounted perpendicular to a direction of a main flow through the valve. The pushrod urges the lever against the clapper when the clapper is in the first position. Also included in the dry pipe valve is a pushrod chamber through which the pushrod extends, the pushrod chamber having an inlet that is fluidly connected to an input supply to the valve, and an outlet. The pushrod is in communication with the lever to allow movement of the lever between the first position and the second position. In one aspect, a dry valve actuator is directly attached to a housing of the pushrod chamber and is connected to the outlet of the pushrod chamber. The drive valve actuator is mounted generally perpendicular to the main flow of the valve.

RELATED APPLICATION

This application incorporates by reference the entire contents of provisional Application No. 62/024,164, filed Jul. 14, 2014, and explicitly incorporates the technical bulletin 358 entitled “Model EX Low Pressure Dry Pipe Valve System” and technical bulletin 359 entitled “Model EX Low Pressure Dry Pipe Valve” included therein, and claims benefit of the filing date of that provisional application under 35 U.S.C. §119(e).

BACKGROUND Field

The present disclosure relates to a dry pipe valve for automatic fire protection sprinkler systems, and in particular a hydraulically-operated valve for use as a primary control valve in a dry pipe, deluge, preaction, or other special types of fire protection systems.

A conventional fire protection system includes automatic sprinklers connected to a conduit to receive pressurized fire-extinguishing fluid, such as water. Such systems are referred to as “wet pipe” systems when the fire-extinguishing fluid fills the conduit such that the fire extinguishing fluid discharges immediately upon the opening of an automatic sprinkler A typical automatic sprinkler has a base with a threaded portion for connection to the conduit and an output orifice to output the fluid to provide fire control and/or suppression. The output orifice is sealed by a seal cap, which is held in place by a release mechanism. The release mechanism is designed to release the cap under predetermined conditions, thereby initiating the flow of fire-extinguishing fluid. A typical release mechanism includes a thermally-responsive element, e.g., a frangible bulb or fusible link.

In certain applications, fire protection systems are installed with at least a portion of the conduit exposed to freezing temperatures. Such installations may include freezers, unconditioned or partially conditioned areas of buildings, or portions of structures that are open to the outside. Fire protection system conduit in spaces subject to freezing temperatures is typically filled with a supervisory gas, such as air or nitrogen, that will not freeze at the surrounding temperature. A valve, referred to as a “dry pipe valve” is used to prevent the flow of fire extinguishing fluid into the conduit until one or more automatic sprinklers have released. The valve is typically designed so that the valve remains closed even with the supervisory gas pressure on the output end of the valve is lower that the pressure of the fire extinguishing fluid on the input end of the valve.

A typical dry pipe valve has a main chamber for controlling fluid flow from the supply input to the system output. The valve also has a secondary, i.e., “sensing” chamber, to which a fluid-based control line is connected. The valve maintains a balance (i.e., a pressure differential) between the pressure in the sensing chamber and the pressure in the fluid supply input line, which is sealed with a cover (referred to as a “clapper”) in the main chamber. A pressure drop in the sensing chamber below a certain threshold allows the clapper to be forced open by the pressure in the supply line, thereby initiating the flow of fluid through the main chamber to the sprinkler system output.

In dry pipe valve systems, the sprinkler conduits initially act as “pilot” lines, which means that the supervisory gas pressure in these conduits serves as a means for detecting a fire condition. In such a system, the pilot lines are connected to the sensing chamber of the dry pipe valve. When a sprinkler is activated under fire conditions, the resulting drop in supervisory gas pressure in the pilot lines (and sensing chamber) triggers the dry pipe valve to initiate the flow of fire-extinguishing fluid to the sprinklers. The sprinklers on the pilot lines (or on a separate set of conduits) then act to extinguish the fire.

A “wet pilot” system may be used in applications where the conduit is not exposed to freezing temperatures. Wet pilot systems contain pressurized fluid, such as water, in pilot lines. In such a system, the pilot lines are connected to the sensing chamber of the dry pipe valve. When a sprinkler is activated under fire conditions, the resulting drop in fluid pressure in the pilot lines (and sensing chamber) triggers the dry pipe valve to initiate the flow of fire-extinguishing fluid to the sprinklers. The sprinklers on the pilot lines (or on a separate set of conduits) then act to extinguish the fire.

Electrically-actuated systems typically employ a solenoid valve that is triggered by electronic fire or smoke detection devices or other types of electrical control devices. The solenoid may be connected in series with a wet or dry pilot system. For example, in a “preaction” system, a loss of pressure in the pilot lines initiates an alarm, but the system does not open the central valve until the solenoid is electrically-actuated, e.g., by an electrical signal from a smoke detection system. Such systems may be used in sensitive areas, such as computer facilities, in which inadvertent activation of the sprinklers would cause significant damage.

SUMMARY

In one example embodiment described herein, a dry pipe valve is provided which includes a main chamber having an input port for receiving fluid from a supply line and further having an output port. The dry pipe valve further includes a clapper assembly installed in the main chamber for sealing the input port. The clapper assembly includes a clapper configured to seal the input port, where the clapper is hinged to the main chamber. The clapper assembly further includes a hinged lever movable between a first position in which the clapper is held closed by the lever and a second position in which the clapper is allowed to open. The dry pipe valve also includes a pushrod mounted perpendicular to a direction of a main flow through the valve and which is connected to the hinged lever. Also included in the dry pipe valve is a pushrod chamber through which the pushrod extends, the pushrod chamber having an inlet that is fluidly connected to an input supply to the valve, and an outlet. The pushrod is in communication with the lever to urge the lever against the clapper in the first position. In some example embodiments the lever has a third position in which the lever prevents the clapper from closing. According to one example embodiment herein, a dry valve actuator is directly attached to a housing of the pushrod chamber and is connected to the outlet of the pushrod chamber. The drive valve actuator is mounted generally perpendicular to the main flow of the valve. In some example embodiments, a handle on the exterior of the valve permits the lever to be moved from the third position to the first position and second position without disassembling the valve.

In some example embodiments, the dry valve actuator includes a diaphragm and a seal which abut against a seat positioned in the outlet of the pushrod chamber, and the dry valve actuator is pressurized on the opposite side of the diaphragm from the pushrod chamber by supervisory gas from the output port of the valve.

According to one example embodiment herein, supply fluid pressure acts on an underside of the clapper and also on the pushrod through the inlet of the pushrod chamber. When supervisory gas pressure is reduced, the dry valve actuator permits fluid from the pushrod camber to drain thereby reducing pressure in the pushrod chamber. When the pressure of the pushrod chamber decreases sufficiently, the pushrod allows the lever to move to the second position and an upward force of the supply pressure beneath the clapper overcomes a force applied by the lever thereby opening the clapper.

In yet another example embodiment, the dry valve actuator is provided with an inlet for allowing in fluid and an outlet for releasing fluid.

According to one example embodiment, a gas pressure in the dry valve actuator is up to and including 40 psi. According to another example embodiment, a gas pressure in the dry valve actuator is between 8 and 25 psi.

Further features and advantages, as well as the structure and operation of various embodiments herein, are described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings claimed and/or described herein are further described in terms of example embodiments. These example embodiments are described in detail with reference to the drawings. These embodiments are non-limiting example embodiments, in which like reference numerals represent similar structures throughout the several views of the drawings and wherein:

FIGS. 1A and 1B are perspective and front views of a dry pipe valve system for an automatic sprinkler system, in accordance with an example embodiment described herein.

FIG. 2 is a view, partly in section, of the dry pipe valve system shown in FIGS. 1A and 1B.

FIGS. 3A and 3B are front and rear perspective views of a dry pipe valve for an automatic sprinkler system, in accordance with an example embodiment described herein.

FIG. 4 is a view, partly in section, of the dry pipe valve shown in FIG. 3.

Any reference numeral that appears in different figures represents the same element in those figures, even if that element is not described separately with respect to each figure.

DETAILED DESCRIPTION

FIGS. 1A, 1B, 3A, and 3B show a dry pipe valve 100, in accordance with an example embodiment, having a body 110 with a main chamber 120 and a pushrod chamber 170. The valve 100 may be formed, for example, of ductile iron, using a casting process. An input port 140 for a high pressure fluid supply line is provided at the bottom of the main chamber 120. The supply line connected to the input port 140 may have an inner diameter of, e.g., about 2 inches, and may provide fluid at a pressure of, e.g., up to about 250 psi or 300 psi. Other sizes also are possible, such as, for example 2.5 inches, 3 inches, 76 mm, 4 inches, 165 mm, 6 inches and 8 inches. A system output port 150, which is connected to a system of sprinkler conduits (not shown), is provided at the top of the main chamber 120. The output port 150 has a nominal diameter the same size as the supply input port 140. The main chamber 120 has an access panel 121 for installation and maintenance of internal parts of the main chamber which are described in detail below in connection with FIG. 2.

FIG. 2 shows a sectional view of the dry pipe valve system shown in FIGS. 1A and 1B. As shown in FIG. 2, a disk-shaped lid, referred to as a clapper 200, seals the input port 140 at the bottom of the main chamber 120. The clapper 200 is connected to the main body by way of a hinge 201. Also connected to the main body 200, opposite the hinge 201, is a lever hinge 210. The lever hinge 210 is movable between a first position in which the clapper 200 is held closed by the lever 210 (shown as 200 a in FIG. 4) and a second position in which the clapper 200 is allowed to open (shown as 200 c in FIG. 4). In addition, the clapper 200 may have a third position in which the lever 210 prevents the clapper 200 from closing (shown as 200 b in FIG. 4). A more detailed description of a clapper assembly can be found, for example, in U.S. Pat. No. 7,673,695, the entire contents of which are incorporated herein by reference.

The pushrod chamber 170 is cylindrically-shaped and extends from the side of the main chamber 120 opposite the position of the clapper 200 hinge 201. The end of the pushrod chamber 170 has a cylindrical housing 170, which has a control fluid input port 171 on the bottom of the housing and a control fluid output port 172 on a side of the housing. The control fluid output port 172 can be perpendicular to the control fluid input port 171.

As noted above, the edge of the clapper 200 opposite the hinge is held in place by a lever 210, which in turn is held in place by a piston 260 and push-rod 230 assembly that extends into the main chamber 120 from the pushrod chamber 130. The push-rod 230 extends from the pushrod chamber 130 into the main chamber 120 through a bore of a threaded, cylindrical push-rod guide that is screwed into the wall between the chambers. The push-rod 230 urges the lever 210 against the clapper 200 when the clapper is in the first position. The push-rod 230 is in communication with the lever 210 to allow movement of the lever 210 between the first position and the second position. In one example embodiment, the push-rod 230 may be about 3 inches in length and about 0.5 inches in diameter (for the embodiment having an input port size of between 2 and 3 inches). A spring 240 surrounds the push-rod guide and is configured to exert force on the piston 260 in a direction away from the main chamber 120. The push-rod guide has a circumferential groove in the bore to receive an o-ring to help seal the space between the push-rod 230 and the guide. In some example embodiments, there is also an O-ring groove at the base of the threaded portion of the guide. The piston 260, push-rod 230, and spring 240 may all be formed, for example, of stainless steel. In some example embodiments, the push-rod guide may be formed, for example, of plastic, and in particular a commercially available acetal resin, such as Delrin® (a trademark of DuPont Corporation).

The pushrod chamber 130 contains pressurized fluid, supplied through the control input port 171, in a volume between the head of the piston 260 and the walls of the pushrod chamber 130. The pressure in the pushrod chamber 130 acts to maintain the piston 260 in the unreleased position against the right side of the pushrod chamber 130 (e.g. urging the pushrod 230 against the lever 210 to maintain the clapper 200 in the first position). The force of the fluid pressure against the piston 260 is countered by force supplied by the spring 240 and the force exerted by the lever 210 against the push-rod 230, due to the upward force on the clapper 200. The control output port 172 is connected to a wet pilot line system.

According to one example embodiment, dry valve actuator 180 is directly attached to the housing of the pushrod chamber 170 so as to be built-in to the dry pipe valve 100. The drive valve actuator 180 is mounted generally perpendicular to the main flow of the valve. The dry valve actuator 180 includes a diaphragm 281 and a seal 283 which abut against a seat 280 positioned in an outlet of the pushrod chamber 170, and the dry valve actuator 180 is pressurized on the opposite side of the diaphragm 281 from the pushrod chamber 170 by supervisory gas from the output port of the valve (e.g., gas provided by a supervisory system 111).

The seat 280 is cylindrical, extends between and through the dry valve actuator 180 and the pushrod chamber 170, and has a port 282 extending roughly along an axis of the seat 280 from a first end of the seat 280 to a second end of the seat 280. A diaphragm 270 is included in the pushrod chamber 170 and separates the fluid in the pushrod chamber from the dry valve actuator 180. The dry valve actuator 180 further includes an inlet 182 and an outlet 181 connected to the supervisory system 111.

When a sprinkler (not shown) operates, there is a loss of air or nitrogen pressure in the sprinkler system's piping (supervisory system 111) which causes the diaphragm 281 and seal 283 in the dry valve actuator 180 to move away from the seat 280. The separation of the seal 283 from the seat 280 allows a releasing discharge of water from the pushrod chamber 170. Since the pressure cannot be replenished through the inlet 171 as rapidly as it is vented from outlet 172, the pushrod chamber 170 pressure falls instantaneously. When the push rod chamber 170 pressure approaches, for example, approximately one-third of the supply pressure, the upward force of the supply pressure acting beneath the clapper 200 overcomes the lever 210 applied force thereby opening the clapper 200, which is shown as 200 c in FIG. 4.

A gas (e.g., air, nitrogen, or a mixture thereof) is supplied to the dry valve actuator 180 through the supervisory system 111 by an automatic tank-mounted air compressor or other continuous air supply sized for the capacity (volume) of the dry pipe system piping, and can be capable of restoring normal air pressure in the system within 30 minutes. When the supervisory gas pressure is reduced, the dry valve actuator permits fluid from the pushrod chamber to drain thereby reducing pressure on the pushrod chamber 170, and when the pressure in the pushrod chamber decreases sufficiently, the lever 210 is permitted to travel to the second position allowing the clapper 200 to open. In one example embodiment, the clapper 200 is maintained in the closed position when a ratio of (1) the fluid pressure in the input port to (2) the supervisory gas pressure in the output port is between 8 and 25. In yet other example embodiments, a ratio of (1) an area of the clapper 200 exposed to the supervisory gas in the output port to (2) the area of the clapper exposed to the fluid in the input port is between 0.5 and 2.0.

In some example embodiments herein, the gas pressure of the dry pipe valve system is preferably between 8 and 28 psi. However, the gas pressure of the dry pipe valve system can be up to and include 40 psi. The gas supply is equipped with an automatic pressure maintenance device (not shown) capable of maintaining a constant system pressure regardless of pressure fluctuations in the compressed air (or nitrogen) source. In some example embodiments, the supervisory gas is air. In other example embodiments, the supervisory gas is not less than 95% nitrogen. Of course, the present disclosure is not limited to such a mixture of nitrogen and air, and other mixtures can be used. The pressure maintenance device includes galvanized trim and brass parts, including a strainer and a field adjustable air pressure regulator, and has a working pressure rating of around 175 psi. The pressure regulator has an adjustable outlet pressure range of 5 to 50 psi.

Once the clapper 200 has opened, the lever 210 acts as a latch, preventing the clapper 200 from returning to the closed position (shown as 200 b in FIG. 4). Water from the supply flows through the dry pipe valve 100 into the system piping. Water also flows through an alarm outlet 290 of the dry pipe valve to alarm devices (not shown). A more detailed description of the operation of the dry pipe valve, upon release of the clapper, can be found in U.S. Pat. No. 7,673,695.

After system shutdown, the dry valve can be reset by pushing in and turning a reset knob 301 as shown in FIG. 3B. The external reset feature of the dry pipe valve allows the clapper 200 to quickly be reset to the close position, without the need to disassemble the valve. In this regard, the reset knob 301 allows the lever to be manually moved from the third position to the second position and to the first position sealing the clapper against the input port.

In the event that water builds up inside the valve due to condensate from the supervisory gas supply system or water is left inside from valve system from testing, a condensate drain port 293 is available for venting. A drain port 292 can also be provided for venting if water is left inside the valve system.

By virtue of the foregoing disclosure, a dry pipe valve can be provided which allows the system's air or nitrogen pressure requirement to be considerably less than the available water supply pressure. As a result, in refrigerated area systems, for example, the lower air pressure can decrease the possibility of ice plugs, which could impede or prevent the flow of water to sprinkler heads in the event of fire. Moreover, lower air pressure (volume) will enable smaller capacity, lower cost dehydration equipment when it is required. Lower air or nitrogen pressure can also reduce water delivery time when the system actuates, and in some cases, may eliminate the need for an accelerator. Low pressure requirements can make the use of dry nitrogen gas, instead of air, practical even on larger systems, resulting in benefits including a lower-than-air dew point, which minimizes ice plugging of system lines, and enhances user friendliness during installation and operation. Lastly, system maintenance can be simplified since priming water is not required and the dry pipe valve can be reset externally without cover removal, providing a significant system-restoration time advantage.

While the present disclosure has been described with respect to what is presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

In addition, it should be understood that the attached drawings, which help to explain functionality described herein, are presented as illustrative examples. The architecture of the present disclosure is sufficiently flexible and configurable, such that it can be utilized and navigated in ways other than shown in the drawings.

Moreover, the purpose of the Abstract is to enable the U.S. Patent and Trademark Office and public generally, and especially scientists, engineers and practitioners in the relevant art(s), who are not familiar with patent or legal terms and/or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical subject matter disclosed herein. The Abstract is not intended to be limiting as to the scope of the present disclosure in any way. It is also to be understood that the procedures recited in the claims need not be performed in the order presented. 

What is claimed is:
 1. A dry pipe valve, comprising: a main chamber having an input port for receiving fluid from a supply line and further having an output port; a clapper assembly installed in the main chamber for sealing the input port, the clapper assembly comprising: a clapper configured to seal the input port, the clapper being hinged to the main chamber; and a hinged lever movable between a first position in which the clapper is held closed by the lever and a second position in which the clapper is allowed to open; a pushrod mounted perpendicular to a direction of a main flow through the valve, the pushrod urging the lever against the clapper when the clapper is in the first position; a pushrod chamber through which the pushrod extends, the pushrod chamber having an inlet that is fluidly connected to an input supply to the valve, and an outlet, wherein the pushrod is in communication with the lever to allow movement of the lever between the first position and the second position; and a dry valve actuator directly attached to a housing of the pushrod chamber and connected to the outlet of the pushrod chamber, the drive valve actuator being mounted generally perpendicular to the main flow of the valve.
 2. The dry pipe valve of claim 1, wherein the dry valve actuator includes a diaphragm and a seal which abut against a seat positioned in the outlet of the pushrod chamber, and the dry valve actuator is pressurized on the opposite side of the diaphragm from the pushrod chamber by supervisory gas from the output port of the valve.
 3. The dry pipe valve of claim 2, wherein supply fluid pressure acts on an underside of the clapper and also on the pushrod through the inlet of the pushrod chamber urging the pushrod against the lever to maintain the clapper in the first position.
 4. The dry pipe valve of claim 3, wherein when supervisory gas pressure is reduced, the dry valve actuator permits water from the pushrod chamber to drain thereby reducing pressure on the pushrod chamber, and when the pressure in the pushrod chamber decreases sufficiently, the lever is permitted to travel to the second position allowing the clapper to open.
 5. The dry pipe valve of claim 3, wherein the clapper is maintained in the closed position when the ratio of (1) the fluid pressure in the input port to (2) the supervisory gas pressure in the output port is between 8 and
 25. 6. The dry pipe valve of claim 1, wherein the lever has a third position, the third position preventing the clapper from closing.
 7. The dry pipe valve of claim 6, wherein the lever is connected to a handle on the exterior of the valve body, the handle allowing the lever to be manually moved from the third position to the second position and to the first position sealing the clapper against the input port.
 8. The dry pipe valve of claim 1, wherein the ratio of (1) the area of the clapper exposed to the supervisory gas in the output port to (2) the area of the clapper exposed to the fluid in the input port is between 0.5 and 2.0.
 9. The dry pipe valve of claim 1, wherein the dry valve actuator comprises an inlet for allowing in fluid and an outlet for releasing fluid.
 10. The dry pipe valve of claim 1, wherein a supervisory gas pressure in the dry valve actuator is up to and including 40 psi.
 11. The dry pipe valve of claim 1, wherein a supervisory gas pressure in the dry valve actuator is between 8 and 25 psi.
 12. The dry pipe valve of claim 1, wherein the supervisory gas is air.
 13. The dry pipe valve of claim 1, wherein the supervisory gas is not less than 95% nitrogen. 